[jart]

That forceinline definition is just tip of the iceberg. It's so hard to define in a way that works with different versions of GCC, -Werror, instrumentation, MSVC, and profiling. If you care about portability, consider just not caring and using static. Too much special casing code can actually make it harder for people in weird environments to use your code, since something is going to break it, and reading past the ifdef soup becomes the biggest obstacle.